/*
* Date prototype extensions. Doesn't depend on any
* other code. Doens't overwrite existing methods.
*
* Adds dayNames, abbrDayNames, monthNames and abbrMonthNames static properties and isLeapYear,
* isWeekend, isWeekDay, getDaysInMonth, getDayName, getMonthName, getDayOfYear, getWeekOfYear,
* setDayOfYear, addYears, addMonths, addDays, addHours, addMinutes, addSeconds methods
*
* Copyright (c) 2006 Jörn Zaefferer and Brandon Aaron (brandon.aaron@gmail.com || http://brandonaaron.net)
*
* Additional methods and properties added by Kelvin Luck: firstDayOfWeek, dateFormat, zeroTime, asString, fromString -
* I've added my name to these methods so you know who to blame if they are broken!
*
* Dual licensed under the MIT and GPL licenses:
* http://www.opensource.org/licenses/mit-license.php
* http://www.gnu.org/licenses/gpl.html
*
*/

/**
* An Array of day names starting with Sunday.
*
* @example dayNames[0]
* @result 'Sunday'
*
* @name dayNames
* @type Array
* @cat Plugins/Methods/Date
*/
Date.dayNames = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];

/**
* An Array of abbreviated day names starting with Sun.
*
* @example abbrDayNames[0]
* @result 'Sun'
*
* @name abbrDayNames
* @type Array
* @cat Plugins/Methods/Date
*/
Date.abbrDayNames = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];

/**
* An Array of month names starting with Janurary.
*
* @example monthNames[0]
* @result 'January'
*
* @name monthNames
* @type Array
* @cat Plugins/Methods/Date
*/
Date.monthNames
= ['January', 'February', 'March', 'April', 'May', 'June', 'July',
'August', 'September', 'October', 'November', 'December'];

/**
* An Array of abbreviated month names starting with Jan.
*
* @example abbrMonthNames[0]
* @result 'Jan'
*
* @name monthNames
* @type Array
* @cat Plugins/Methods/Date
*/
Date.abbrMonthNames = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

/**
* The first day of the week for this locale.
*
* @name firstDayOfWeek
* @type Number
* @cat Plugins/Methods/Date
* @author Kelvin Luck
*/
Date.firstDayOfWeek = 1;

/**
* The format that string dates should be represented as (e.g. 'dd/mm/yyyy' for UK, 'mm/dd/yyyy' for US, 'yyyy-mm-dd' for Unicode etc).
*
* @name format
* @type String
* @cat Plugins/Methods/Date
* @author Kelvin Luck
*/
Date.format = 'dd/mm/yyyy';
//Date.format = 'mm/dd/yyyy';
//Date.format = 'yyyy-mm-dd';
//Date.format = 'dd mmm yy';

/**
* The first two numbers in the century to be used when decoding a two digit year. Since a two digit year is ambiguous (and date.setYear
* only works with numbers < 99 and so doesn't allow you to set years after 2000) we need to use this to disambiguate the two digit year codes.
*
* @name format
* @type String
* @cat Plugins/Methods/Date
* @author Kelvin Luck
*/
Date.fullYearStart = '20';

(function() {

/**
* Adds a given method under the given name
* to the Date prototype if it doesn't
* currently exist.
*
* @private
*/
function add(name, method) {
if( !Date.prototype[name] ) {
Date.prototype[name] = method;
}
};

/**
* Checks if the year is a leap year.
*
* @example var dtm = new Date("01/12/2008");
* dtm.isLeapYear();
* @result true
*
* @name isLeapYear
* @type Boolean
* @cat Plugins/Methods/Date
*/
add("isLeapYear", function() {
var y = this.getFullYear();
return (y%4==0 && y%100!=0) || y%400==0;
});

/**
* Checks if the day is a weekend day (Sat or Sun).
*
* @example var dtm = new Date("01/12/2008");
* dtm.isWeekend();
* @result false
*
* @name isWeekend
* @type Boolean
* @cat Plugins/Methods/Date
*/
add("isWeekend", function() {
return this.getDay()==0 || this.getDay()==6;
});

/**
* Check if the day is a day of the week (Mon-Fri)
*
* @example var dtm = new Date("01/12/2008");
* dtm.isWeekDay();
* @result false
*
* @name isWeekDay
* @type Boolean

* @cat Plugins/Methods/Date

*/

add("isWeekDay", function() {

return !this.isWeekend();

});



/**

* Gets the number of days in the month.

*

* @example var dtm = new Date("01/12/2008");

* dtm.getDaysInMonth();

* @result 31

*

* @name getDaysInMonth

* @type Number

* @cat Plugins/Methods/Date

*/

add("getDaysInMonth", function() {

return [31,(this.isLeapYear() ? 29:28),31,30,31,30,31,31,30,31,30,31][this.getMonth()];

});



/**

* Gets the name of the day.

*

* @example var dtm = new Date("01/12/2008");

* dtm.getDayName();

* @result 'Saturday'

*

* @example var dtm = new Date("01/12/2008");

* dtm.getDayName(true);

* @result 'Sat'

*

* @param abbreviated Boolean When set to true the name will be abbreviated.

* @name getDayName

* @type String

* @cat Plugins/Methods/Date

*/

add("getDayName", function(abbreviated) {

return abbreviated ? Date.abbrDayNames[this.getDay()] : Date.dayNames[this.getDay()];

});



/**

* Gets the name of the month.

*

* @example var dtm = new Date("01/12/2008");

* dtm.getMonthName();

* @result 'Janurary'

*

* @example var dtm = new Date("01/12/2008");

* dtm.getMonthName(true);

* @result 'Jan'

*

* @param abbreviated Boolean When set to true the name will be abbreviated.

* @name getDayName

* @type String

* @cat Plugins/Methods/Date

*/

add("getMonthName", function(abbreviated) {

return abbreviated ? Date.abbrMonthNames[this.getMonth()] : Date.monthNames[this.getMonth()];

});



/**

* Get the number of the day of the year.

*

* @example var dtm = new Date("01/12/2008");

* dtm.getDayOfYear();

* @result 11

*

* @name getDayOfYear

* @type Number

* @cat Plugins/Methods/Date

*/

add("getDayOfYear", function() {

var tmpdtm = new Date("1/1/" + this.getFullYear());

return Math.floor((this.getTime() - tmpdtm.getTime()) / 86400000);

});



/**

* Get the number of the week of the year.

*

* @example var dtm = new Date("01/12/2008");

* dtm.getWeekOfYear();

* @result 2

*

* @name getWeekOfYear

* @type Number

* @cat Plugins/Methods/Date

*/

add("getWeekOfYear", function() {

return Math.ceil(this.getDayOfYear() / 7);

});



/**

* Set the day of the year.

*

* @example var dtm = new Date("01/12/2008");

* dtm.setDayOfYear(1);

* dtm.toString();

* @result 'Tue Jan 01 2008 00:00:00'

*

* @name setDayOfYear

* @type Date

* @cat Plugins/Methods/Date

*/

add("setDayOfYear", function(day) {

this.setMonth(0);

this.setDate(day);

return this;

});



/**

* Add a number of years to the date object.

*

* @example var dtm = new Date("01/12/2008");

* dtm.addYears(1);

* dtm.toString();

* @result 'Mon Jan 12 2009 00:00:00'

*

* @name addYears

* @type Date

* @cat Plugins/Methods/Date

*/

add("addYears", function(num) {

this.setFullYear(this.getFullYear() + num);

return this;

});



/**

* Add a number of months to the date object.

*

* @example var dtm = new Date("01/12/2008");

* dtm.addMonths(1);

* dtm.toString();

* @result 'Tue Feb 12 2008 00:00:00'

*

* @name addMonths

* @type Date

* @cat Plugins/Methods/Date

*/

add("addMonths", function(num) {

var tmpdtm = this.getDate();



this.setMonth(this.getMonth() + num);



if (tmpdtm > this.getDate())

this.addDays(-this.getDate());



return this;

});



/**

* Add a number of days to the date object.

*

* @example var dtm = new Date("01/12/2008");

* dtm.addDays(1);

* dtm.toString();

* @result 'Sun Jan 13 2008 00:00:00'

*

* @name addDays

* @type Date

* @cat Plugins/Methods/Date

*/

add("addDays", function(num) {

//this.setDate(this.getDate() + num);

this.setTime(this.getTime() + (num*86400000) );

return this;

});



/**

* Add a number of hours to the date object.

*

* @example var dtm = new Date("01/12/2008");

* dtm.addHours(24);

* dtm.toString();

* @result 'Sun Jan 13 2008 00:00:00'

*

* @name addHours

* @type Date

* @cat Plugins/Methods/Date

*/

add("addHours", function(num) {

this.setHours(this.getHours() + num);

return this;

});



/**

* Add a number of minutes to the date object.

*

* @example var dtm = new Date("01/12/2008");

* dtm.addMinutes(60);

* dtm.toString();

* @result 'Sat Jan 12 2008 01:00:00'

*

* @name addMinutes

* @type Date

* @cat Plugins/Methods/Date

*/

add("addMinutes", function(num) {

this.setMinutes(this.getMinutes() + num);

return this;

});



/**

* Add a number of seconds to the date object.

*

* @example var dtm = new Date("01/12/2008");

* dtm.addSeconds(60);

* dtm.toString();

* @result 'Sat Jan 12 2008 00:01:00'

*

* @name addSeconds

* @type Date

* @cat Plugins/Methods/Date

*/

add("addSeconds", function(num) {

this.setSeconds(this.getSeconds() + num);

return this;

});



/**

* Sets the time component of this Date to zero for cleaner, easier comparison of dates where time is not relevant.

*

* @example var dtm = new Date();

* dtm.zeroTime();

* dtm.toString();

* @result 'Sat Jan 12 2008 00:01:00'

*

* @name zeroTime

* @type Date

* @cat Plugins/Methods/Date

* @author Kelvin Luck

*/

add("zeroTime", function() {

this.setMilliseconds(0);

this.setSeconds(0);

this.setMinutes(0);

this.setHours(0);

return this;

});



/**

* Returns a string representation of the date object according to Date.format.

* (Date.toString may be used in other places so I purposefully didn't overwrite it)

*

* @example var dtm = new Date("01/12/2008");

* dtm.asString();

* @result '12/01/2008' // (where Date.format == 'dd/mm/yyyy'

*

* @name asString

* @type Date

* @cat Plugins/Methods/Date

* @author Kelvin Luck

*/

add("asString", function(format) {

var r = format || Date.format;

return r

.split('yyyy').join(this.getFullYear())

.split('yy').join((this.getFullYear() + '').substring(2))

.split('mmmm').join(this.getMonthName(false))

.split('mmm').join(this.getMonthName(true))

.split('mm').join(_zeroPad(this.getMonth()+1))

.split('dd').join(_zeroPad(this.getDate()));

});



/**

* Returns a new date object created from the passed String according to
Date.format or false if the attempt to do this results in an invalid
date object

* (We can't simple use Date.parse as it's not aware of locale and I
chose not to overwrite it incase it's functionality is being relied on
elsewhere)

*

* @example var dtm = Date.fromString("12/01/2008");

* dtm.toString();

* @result 'Sat Jan 12 2008 00:00:00' // (where Date.format == 'dd/mm/yyyy'

*

* @name fromString

* @type Date

* @cat Plugins/Methods/Date

* @author Kelvin Luck

*/

Date.fromString = function(s)

{

var f = Date.format;

var d = new Date('01/01/1977');



var mLength = 0;



var iM = f.indexOf('mmmm');

if (iM > -1) {

for (var i=0; i<Date.monthNames.length; i++) {

var mStr = s.substr(iM, Date.monthNames[i].length);

if (Date.monthNames[i] == mStr) {

mLength = Date.monthNames[i].length - 4;

break;

}

}

d.setMonth(i);

} else {

iM = f.indexOf('mmm');

if (iM > -1) {

var mStr = s.substr(iM, 3);

for (var i=0; i<Date.abbrMonthNames.length; i++) {

if (Date.abbrMonthNames[i] == mStr) break;

}

d.setMonth(i);

} else {

d.setMonth(Number(s.substr(f.indexOf('mm'), 2)) - 1);

}

}



var iY = f.indexOf('yyyy');



if (iY > -1) {

if (iM < iY)

{

iY += mLength;

}

d.setFullYear(Number(s.substr(iY, 4)));

} else {

if (iM < iY)

{

iY += mLength;

}

// TODO - this doesn't work very well - are there any rules for what is meant by a two digit year?

d.setFullYear(Number(Date.fullYearStart + s.substr(f.indexOf('yy'), 2)));

}

var iD = f.indexOf('dd');

if (iM < iD)

{

iD += mLength;

}

d.setDate(Number(s.substr(iD, 2)));

if (isNaN(d.getTime())) {

return false;

}

return d;

};



// utility method

var _zeroPad = function(num) {

var s = '0'+num;

return s.substring(s.length-2)

//return ('0'+num).substring(-2); // doesn't work on IE :(

};



})();